1. Field of the Invention
The present invention relates to an antenna, incorporated in a radio device, that has a radiated element preferred for mobile radio devices, portable telephones, portable information terminals, etc.
2. Description of the Related Art
Recently, there are demands for even lighter, more compact, and thus handier, portable telephones, etc. This, at the same time, requires lighter and more compact antennas used for these devices.
When realizing a compact frame for portable telephones, etc., the printed board inside the device should desirably be held as small as possible. However, the portion used to mount the printed board onto the frame is necessary. In order to ensure that the mount portion has a predetermined mechanical strength, no components can be mounted onto the portion where the printed board and frame are in contact. This portion is mostly left as dead space on the printed board.
Also, incorporating the antenna into the device conventionally required a large number of components. For example, Patent Laid-Open Hei 9(1997)-321529 Publication discloses many components in FIG. 1: a printed board, an incorporated antenna (1), components (5,6) for connecting the antenna with the board, and additional supporting structures. Not only do these components take up large space inside the housingxe2x80x94they also require additional manufacturing steps and create non-uniform property due to contact failure and component irregularities.
Furthermore, conventional incorporated antennas had insufficient property due to changing directivity according to the shape of the printed board and the mounted position of the antenna.
The present invention aims at solving the above problems by providing an antenna for a radio device that efficiently uses the space inside the device, ensures sufficient mechanical strength, and can be made compact without entailing deterioration in property. This results in making the whole radio device more compact.
The antenna for a radio device according to the present invention includes a circuit board arranged within the radio device body; a first radiating element and a second radiating element arranged in axial symmetry to each other on said circuit board; and a feeding point for feeding each of said first radiating element and said second radiating element in equiphase, wherein said first radiating element and said second radiating element are respectively provided at the ends of said circuit board, and the feeding points of said first radiating element and said second radiating element are respectively provided in the vicinity of the corners of said circuit board.
This structure permits the antenna to be arranged in the vicinity of the transmitting/receiving and other circuits without incurring deterioration in antenna property.